. The investigators propose development of a new class of perfluoropolymers with exceptionally high oxygen flux as non-porous membranes for enhanced bioreactor performance. Propagation of animal cells for biopharmaceuticals is becoming widespread along with optimization of environmental constraints and procedures to increase bioreactor output. Often oxygen availability limits bioreactor cell culture production. Sparging is the choice method to aerate microbial cultures, but with sensitive animal cells sparging can be counterproductive. Entertainment at liquid/gas interface often damages animal cells. Microporous hollow fibers to introduce oxygen also causes shear damage to animal cells. Animal cells also tend to attach to microporous fibers and impede gas transfer. The copolymer of perfluoro-dimethyl-dioxole (PDD) and tetrafluoroethylene (TFE) display membrane permeabilities 40 times higher than conventional membranes (e.g. silicone rubber). The PDD-TFE organophobic and hydrophobic surface should discourage cell surface attachment and clogging. The investigators will make both hollow fiber and flat sheet oxygenator modules which will be evaluated with mammalian cells in bioreactors to determine their oxygen transfer rates, non- plugging characteristics and their ability to support cell cultures having enhanced oxygen uptake rates.